Catalysts and methods for alcohol dehydration

a technology of aromatic alcohol and catalysts, which is applied in the direction of physical/chemical process catalysts, ether preparation by compound dehydration, ether preparation, etc., can solve the problems of less pure product, difficult handling, and potential cost, and achieve the effect of remarkable selectivity

Inactive Publication Date: 2015-06-09
DOW GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The first route, for example where chlorobenzene reacts with phenol in the presence of caustic and a copper catalyst, typically leads to less pure product and requires high pressure (5000 psig), uses an expensive alloy reactor and produces stoichiometric quantities of sodium chloride.
A major drawback of thoria however is its radioactive nature, which makes its handling difficult and potentially costly.
Furthermore, the supply of thoria globally has been largely unavailable in recent years putting at risk existing DPO manufacturers utilizing this technology.
Additionally, other catalysts for the gas-phase dehydration of phenol, such as zeolite catalysts, titanium oxide, zirconium oxide and tungsten oxide, generally suffer from lower activity, significantly higher impurity content and fast catalyst deactivation.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0036]The synthesis of lanthanum oxychloride is carried out by thermal decomposition of LaCl3·7H2O. A sample of the powdered precursor (approximately 10 g) is calcined in air in a static calcination oven under the following temperature protocol: ramp 1.41° C. / min to 550° C., dwell 3 hrs at 550° C., cool down to room temperature. The elemental composition of the catalyst is assayed by X-ray fluorescence spectroscopy (XRF) to 17.23 wt. % chlorine, 69.63 wt. % lanthanum and 13.14 wt. % oxygen (balance). Thus, the elemental composition of the catalyst is La1.00O1.64Cl0.97. The specific surface area (BET) of the catalyst sample is measured to 6.2 m2 / g and its pore volume to 0.013 cm3 / g. The XRD data shows the presence of lanthanum oxychloride phases.

example 2

[0037]The lanthanum oxychloride catalyst from Example 1 is used for the dehydration of phenol. The powder is pressed and sieved to obtain particles that are between 0.60 mm and 0.85 mm in diameter. The particles are loaded into an electrically heated stainless steel reactor tube and heated to the reaction temperature with nitrogen flowing through the tube. After the reaction temperature is reached, vapor-phase phenol is passed through the reactor tube. The conversion of phenol is carried out at a weight hourly space velocity of 1 (WHSV=gram phenol / gram catalyst-hour) and at 500° C. Test conditions and results are shown in Table 1.

[0038]

TABLE 1ConversionSelectivity [mol. %]Test[mol. %]DiphenylConditionsPhenolOxideOPPDBFO-BIPPEM-BIPPEP-BIPPET = 500° C.0.70%95.86%0.02%4.12%0.00%0.00%0.00%Feed: PhOHToS = 1.5 hrsWHSV 1 hr−1T = 500° C.0.82%95.83%0.07%4.09%0.00%0.00%0.00%Feed: PhOHToS = 2.75 hrsWHSV 1 hr−1T = 500° C.0.82%95.90%0.18%3.93%0.00%0.00%0.00%Feed: PhOHToS = 3.75 hrsWHSV 1 hr−1T =...

example 3

[0039]A 1M LaCl3 solution, prepared by dissolving 50.00 g LaCl3 in 135 mL DI H2O, is added dropwise over 15 min into a 2L flask equipped with an overhead stirrer and an initial 500 mL DI H2O. The solution is stirred at 400 rpm with a 6 mm PTFE screw propeller blade. Approximately 182 mL of tetrapropylammonium hydroxide is added during the precipitation to keep the pH at a constant value of 9. The resulting white precipitate is allowed to age in solution for 1 h without stirring, after which time it is centrifuged at 7000 rpm for 5 min. The decanted precipitate is placed into an oven, dried at 120° C. for 4 h and calcined at 500° C. for 4 h with a ramp rate of 5° C. / min to give 23 g of product. Neutron activation analysis (NAA) reveals a total chlorine concentration of 5.8 wt %.

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Abstract

Provided is a process for preparing a diaryl ether compound through the dehydration of an aromatic alcohol compound in the presence of a dehydration catalyst. The dehydration catalyst is an oxide of a light rare earth element, wherein the light earth element is lanthanum, praseodymium, neodymium, or mixtures thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority from provisional application Ser. No. 61 / 653,493, filed May 31, 2012, which is incorporated herein by reference in its entirety.BACKGROUND[0002]This invention relates generally to catalysts and methods for the dehydration of aromatic alcohol compounds to ethers. More particularly, the invention uses a dehydration catalyst comprising an oxide of a light rare earth element for the dehydration of aromatic alcohol compounds to diaryl ethers.[0003]Diaryl ethers are an important class of industrial materials. Diphenyl oxide (DPO), for instance, has many uses, most notably as the major component of the eutectic mixture of DPO and biphenyl, which is the standard heat transfer fluid for the concentrating solar power (CSP) industry. With the current boom in CSP has come a tightening of the supply of DPO globally and questions surrounding the sustainability of the technology have arisen.[0004]Diaryl ethers are curren...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C07C41/09B01J37/02B01J35/10B01J35/00B01J27/10B01J21/06B01J37/03C09K5/10
CPCC07C41/09B01J37/031B01J21/066B01J27/10B01J35/002B01J35/1009B01J35/1038B01J37/0201C09K5/10C07C43/275
Inventor BARTON, DAVID G.CHOJECKI, ADAMELOWE, PAUL R.KILOS, BEATA A.STANGLAND, ERIC E.
Owner DOW GLOBAL TECH LLC
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